In certain surgical operations, for example and in particular in heart surgery, and also in the case of severe injuries or wounding, a patient may very often suffer from substantial blood losses which must be compensated by immediate blood transfusion if the life of the patient is not to be put at risk. Particularly in the case of surgical operations, the loss of blood is such that the blood which has been lost from the body is often still available, namely being in the form of accumulations of blood in cavities in the body of the patient, to which the surgeon has relatively ready access. It is therefore already known for the blood to be collected from such accumulations in the body, and re-infused into the same patient. Such a procedure which involves collecting the blood from and re-infusing the collected blood into the same patient is referred to as intra-operative autotransfusion.
Particularly in the case of heart surgery, for the purposes of performing autotransfusion, it is known for the patient to be connected to a heart lung machine for sucking the blood from the patient by means of pumps installed in the machine, and re-supplying the blood to the patient. However, such machines are extremely expensive and are therefore not available in every operating theatre, while in addition, in spite of the blood being carefully treated in machines of that type, the blood, being a fluid that is very sensitive and easily damaged, may nonetheless suffer a certain amount of damage, in its comparatively long path of flow through the machine from the patient and back to the patient again.
In an effort to remedy that problem, an apparatus has been put forward, for receiving and re-infusing a patient's own blood, wherein the blood is sucked in by way of a suction head, a suction line connected thereto and a suction connection, into a rigid container. The container communicates by way of at least one further connection with a vacuum source which is operative to produce, within the container, the reduced pressure required for sucking the blood from the patient. The container may have for example a capacity of about 2000 cm.sup.2, and when the container is completely or substantially filled, the suction line is clamped off, the line connecting to the vacuum source is disconnected from the above-mentioned further vacuum connection and a conventional infusion fitment, possibly with a blood filter disposed on the upstream side thereof, is then fitted to the further connection from which the suction line as removed, so that the blood in the container can be infused back into the patient in the usual manner.
Although that arrangement has the advantage that the blood can be taken from the patient over a short flow path, thereby substantially avoiding damage to the blood, nonetheless it suffers from some disadvantages which mean that it is not entirely satisfactory. A major disadvantage is that that apparatus can only be used to re-infuse the blood from the container, into a blood vessel in the patient, in the manner of a conventional blood transfusion. As however an autotransfusion operation of the kind concerned herein is effected whenever a patient has suffered serious blood losses, it is also a point of major importance that the blood is re-infused back into the patient in the shortest possible time, as otherwise the patient may suffer from a considerable deficiency of body blood, such as to endanger the patient's life, over a considerable period of time. Such rapid re-infusion of blood can generally only be achieved by pressure infusion of the blood taken from the patient, but the above-described known apparatus is not designed to perform such pressure infusion and in addition, in consequence, such a pressure infusion cannot be effected without the danger of inducing an air embolism in the patient. Another disadvantage of the known apparatus is that, after an accumulation of blood in the patient's body has been drawn into the container, it is necesary to prevent air from being drawn into the container after the blood, which is effected by the suction line being closed off by means of a clamp; however, the suction force produced by the vacuum source still continues to apply a suction effect within the rigid container, and that may also give rise to the not inconsiderable danger of damaging the blood, as for example the reduced pressure or suction force may cause excessive expansion of the red blood corpuscles, and may even cause them to burst.
In another apparatus for intra-operative autotransfusion, which is similar to the apparatus just discussed above, the patient's blood is initially sucked into a rigid container and then re-infused into the patient from that container by means of a blood pump (see U.S. Pat. Nos. 4,047,521 and 4,033,345). In one embodiment of that known apparatus, the blood pump which is connected to the container is formed by an axially compressible concertina or harmonica-like arrangement which is releasably connected to the container and which can be operated to produce a vacuum which can overcome the vacuum in the rigid container. The harmonica-like arrangement is disconnected from the rigid container, after it is filled with blood, and handed over to the anaesthetist for the purposes of the re-infusion operation. In another form of the known apparatus, the blood pump is formed by a further container and is non-releasably connected to the rigid container in which the blood is received from the patient's body. The blood pump has a third inner, yieldably deformable container, and a respective check valve at its inlet and its outlet. The deformable container is compressed and re-expanded by alternately applying an increased pressure and a reduced pressure to a connection on the deformable container, so that in that way, and with the two check valves being suitably operative, the blood is sucked out of the first rigid container and then passed on to the patient through the outlet valve.
Although that apparatus permits the blood to be rapidly reinfused into the patient, it suffers from the disadvantage that the blood comes into contact with a comparatively large surface area which is foreign to the blood, namely the surfaces in the rigid container and in the blood pump, while in addition there is the danger for the blood to be detrimentally effected and possibly damaged by the vacuum produced in the blood pump, being a stronger vacuum than that in the rigid container.